Traffic-bearing surfaces such as roadways and walkways, whether constructed of asphalt or concrete materials are subject to wear and deterioration from vehicular traffic, from thermal expansion and contraction, rain and freezing weather conditions, and also from settling and ground-shifting such that it is common for surface cracks and potholes to develop. These cracks and holes if left unattended can result in further and more severe roadway damage. For this reason, it has become a common practice to fill the cracks and holes with a material which will restore the surface, exclude water, and otherwise repair the roadway. A smooth surface is preferably restored so that increased pressure due to bouncing wheels and the like will be avoided.
Currently, for crackfilling, high temperature asphalt and rubber mixtures are used, which when applied to the cracks at a high temperature are in a fluid state so that they flow into the crack to leave a substantially level surface. Cooling to standard atmospheric temperatures quickly hardens the hot asphalt and rubber mixture. Hot patching of potholes and hot paving of roadways is also common. Typically, the patching or paving material is mixed and heated in an aggregate to a plastic consistency. It is pressed or rolled to provide a smooth surface. The methods and materials require that the asphalt or rubber material be maintained for application at elevated and often dangerously high temperature levels. At such elevated temperatures, contact with the material before it cools, can causing burning. Also, there is a risk of ignition of the fumes.
Ductile asphalt emulsions comprising asphalt and resins and/or maltines which partially dissolve or anneal the existing asphalt roadway have also been used for road repair. The volatility and expense of applying such materials is often undesirable. Sanding or the application of an aggregate following the application of the ductile emulsion is usually required.
Alternatively, water emulsions comprising emulsified asphalt are available for mixing with aggregate. However, such materials are available in two (2) forms, both of which are inappropriate for crackfilling, and one of which is inappropriate for pothole patching and paving. First, there are cationic emulsions which set so quickly that they must have a retarder added to the mix so that it can be mixed without setting up in the mixer. Such materials with a retarder are not suitable for crackfilling because they are too thin to fill a crack and do not expand and contract without additives. Also, cationic emulsions do not always mix with the type of aggregate rock chips available in a given locality and therefore, results in additional expense for importing rock chips with appropriate characteristics for proper mixing.
Other emulsions which are available are anionic emulsions composed of water emulsified asphalt. However, the anionic emulsions are extremely slow setting and remain liquid at standard atmospheric temperatures for long periods of time. Such anionic emulsions have been useful for operations such as "fog sealing" of roadways in which an extremely light and thin coating of the emulsion is dispersed as a mist or a fog over a wide area. However, the application of anionic emulsions to cracks or potholes results in a fluid or plastic pool of the emulsion which is extremely slow to set up. Many hours or even a number of days are required for setting to take place. This disadvantageously requires the traffic area to be closed for an extended period of time and can be cost-prohibitive where the use of the roadway or traffic area is necessary for daily commerce.